Machines, such as grinders and chippers, are used for shredding, grinding, and/or chipping a variety of materials. For the purposes of this disclosure, the representative environment in which the principles of the invention are described will be that of a common tub grinder as tub grinders are illustrative of chipping and grinding machines. References herein to tub grinders and the features thereof, however, are not intended to be limiting as the principles of the invention are generally applicable to machines configured to reduce larger materials into smaller materials.
Grinders and chippers typically include a grinding or chipping chamber that houses a chipping or grinding device. The grinding device of a typical tub grinder includes a hammermill or hog, an anvil, and a screen that function cooperatively to reduce larger materials into smaller materials. Tub grinders typically include a grinding chamber that has a tub shaped portion that surrounds a portion of the hammermill or hog. The tub shaped portion is configured to rotate about a vertical axis while hammermill or hog is configured to rotate about a horizontal axis. Examples of tub grinder are shown and described in U.S. Pat. No. 5,507,441 to De Boef et al.; U.S. Pat. No. 5,950,942 to Brand et al.; and U.S. Pat. No. 6,840,471 to Roozeboom et al, all of which are presently assigned to Vermeer Manufacturing Company.
Typically the hammermills or hogs of the tub grinder include a number of grinding members such as cutters that are mounted to a cylindrical drum. Wear of the grinding members can limit the efficiency and effectiveness of the entire grinding system. In particular, wear of the grinding members can result in loss of hammer integrity, out-of-balance drum conditions, and increases in maintenance and service costs.
Advancements in the grinding and chipping arts have resulted in improved drum and grinding members. For example, U.S. Pat. No. 6,840,471 to Roozeboom et al. and U.S. Pat. No. 6,422,495 to De Boef et al. disclose a cylindrical grinding drum that includes grinding members that are more easy to replace than those of the prior art. Nonetheless, further improvements relating to the durability and effectiveness of grinding and chipping machines are desirable.